Electric circuit-breaker with compressed gas blow-out



Aug. 4, 1936. c c 2,049,995

ELECTRI CIRCUIT BREAKER WITH COMPRESSED GAS BLOW-OUT Filed July 6, 1951 Patented Aug. 4, 1936 PATENT OFFICE ELECTBId CIRCUIT-BREAKER WITH COMPRESSED GAS BLOW-OUT Andr Clerc, Villcurbanne, France, assignor to Ateliers de Constructions Electriques de Belle,

Paris, France Application July 6, 1931, Serial No. 549,001 In Germany August 4, 1930 5 Claims. (01. 200-148) The present invention relates to an improvement in or modification of the electric circuit breaker described in my co-pending U. S. application No. 503,835, filed December 20th, 1930,

5 and in which an arc is extinguished by gas under pressure.

In said patent application is described a circuit-breaker provided with relatively movable contacts and having one low ohmic resistance connected to one contact and to a stationary electrode located behind the contacts, so that the arc being struck at first between the two contacts is blown on to the said electrode.

The present invention, which relates to an 15 improvement in such circuit-breakers, has for its object a circuit-breaker in which the arc, struck at first between the two contacts, is blown by a gas unto several stationary electrodes connected, together and to one of said contacts, by,

20 low ohmic resistances; the movable contact being displaced perpendicularly to the direction of the blast, and the whole arranged so that several intermediate points of the are formed between the contacts are blown on to the electrodes,

25 whereby these arc fractions are shunted by a resistance and extinguished, the remaining portions of the are being thus placed in series with said resistances.

Another object of the present invention con- 30 sists in disposing the stationary electrodes symmetrically on two opposite sides of the arc chute.

As an example, and for purposes of illustration, a drawing is hereto annexed wherein:

Figure 1 is a vertical sectional view of the circuit breaker, and

Figure 2 is a plan view of the blowing chute.

Referring to the drawing, the circuit breaker is formed by a fixed contact i and a contact 2 movable in the horizontal direction. The mov- 40 able contact passes through the walls of a tube 3 through which, as indicated by an arrow, the gas for extinguishing purposes passes in vertical direction. An arc chute 4 of insulating material is provided at one of the ends of the passage 3 45 near the contacts. This chute is formed by two parallel sides 5 connected by two divergent walls 6. Said walls 6 are extended by horns I each of said horns being electrically connected to one of the contacts I and 2. Each of the horns is 50 connected, moreover, to a series of low ohmic resistance elements 8 and 8" connected together. The free end of each said series of resistances is connected to a stationary electrode 9 formed, for

example, by 'a plate of electrically conducting 5 material. The common'terminal of two adjanot shunted.

cent resistance elements 8 and 8 is connected to another stationary electrode 'll similar to electrode 9. In the centre of the chute and in the space between the two electrodes 9 is located a metallic plate I electrically insulated from the electrodes and contacts. All said stationary electrodes 9 and II and said plate I!) are disposed.

radially in the divergent chute- 4. Walls l2 of insulating material fixed to the sides 5 of the chute extend the stationary electrodes and the 10 plates l0 towards the outlet of the chute. Furthermore, all said stationary electrodes and plate III are disposed radially in the divergent chute, symmetrically on its two opposite sides. The chute 4 is thus of fan-tail shape and has a numl5 ber of divergent chambers in the form of pyramids.

The circuit-breaker operates as follows;

At the moment when the contacts of the circuit breaker separate, the are thus formed is at once curved and blown upwardly by the current of air directed perpendicularly to the displaceg 'ment of the contact 2 and is driven unto the horns I. Under the influence of the blast, the two roots of the are are rapidly displaced along said horns, and intermediate points of said are blown-unto the stationary electrodes 9 and II and the metallic plate l0. Thus, the arc is cut up into as many fractions as there are chambers formed in the chute by the horns "I, plate I0 and electrodes 9, II. The two ends of all these fractions of the arc travel along the metal partitions I, 9, l0, ll until they reach the base of the insulating walls I 2 where they are arrested, whereas under the influence of the blast the central portion of these fractions of the arc increase their curvature towards the outlet of the chute. On the other hand, ashort instant after the opening of the contacts, at the instant when intermediary points of the arc 'I--! come in contact with the stationary electrodes 9, II, the extreme fractions '|l|, ll-9 of the arc shunt the resistances 8 and 8 of low ohmic value. As

\ the resistance of these fractions of the are become very rapidly greater than the ohmic value of resistances 8, 8 these fractions cannot subsist and are extinguished at once. The intensity of the current to be interrupted thus falls oflf very rapidly, while its phase displacement on the voltage diminishes and the voltage of the circuit to be interrupted is thus almost entirely absorbed. This lowering of the voltage is produced. by the resistances 8, 8' and by the arcs Quenching of the arc mayv thus take place in less than ahalf cycle since the progressive reduction in the intensity is considerably accelerated without the necessity of awaiting the natural passage to zero of the intensity of the current, in order to insert the resistances.

For certain purposes the construction of the apparatus may be simplified by dispensing with the plate It], the electrodes M and even with one of the horns 1 together with its resistance.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. In an electric circuit breaker relatively movable contacts between which an arc is adapted to be struck; means to blow a gas blast against said are in a direction transverse to the path of relative movement of said contacts; a' chute surrounding said are lengthened by said blast; stationary electrodes mounted in said chute behind said contacts viewed in the direction of said blast and having their free ends directed toward said contacts substantially in the plane of the latter; ohmic resistances connected between the electrodes, one of said electrodes at least being connected to one of said contacts, the whole being arranged so that several intermediate points of the arc formed between said contacts will be blown onto the free ends of said electrodes, whereby fractions of said arc are shunted by a resistance and extinguished, the remaining portions of said arc being thus placed in series with said resistances.

2 In an electric circuit breaker relatively movable contacts between which an arc is adapted to be struck; means to blow a gas blast against said are in a direction transverse to the path of relative movement of said contacts; a chute surrounding the arc lengthened by said blast; stationary, converging electrodes mounted in said chute substantially in the plane of said contacts and beyond the latter viewed in the direction of said blast and having their free ends directed toward said contacts; ohmic resistances connected between said electrodes, one of said electrodes at least being connected to one of said contacts, the whole being arranged so that several intermediate points along the are formed between said contacts are blown against said electrodes, whereby fractions of said arc are shunted by a resistance and extinguished, the remaining portions of said are being thus placed in series with said resistances.

3. In an electric circuit breaker, a divergent arc chute, relatively mobile contacts in said chute, several stationary electrodes in said chute, said electrodes being disposed symmetrically on two opposite sides of this chute, ohmic resistances connected between the stationary electrodes on each side of said chute, a metallic plate disposed in the centre of said chute between the electrodes of the two sides and electrically insulated from said electrodes, walls of insulating material prolonging said metallic plate towards the outlet of said chute, and means for blowing a blast of gas insaid chute transversely to the trajectory of the movable contact and in the direction of said electrodes. i

4. In an electric circuit breaker, an arc chute having divergent opposed walls; relatively movable contacts in said chute; stationary electrodes disposed radially in said chute substantially in the plane of said contacts and having their free ends directed toward the latter; ohmic resistances connected between said electrodes, one of said electrodes at least being connected to one ofsaid contacts; and means for blowing a-gas blast in said chute transversely to the path of relativemovement of said contacts and along said electrodes.

are chute, relatively'movable contacts in said 35 chute, several stationary electrodes disposed radially in said divergent chute, said electrodes being prolonged towards the outlet of said chute by plates of insulating material, ohmic resistances connected between said electrodes, one of said electrodes at least being connected to one of said contacts, and means for blowing a blast of gas in said chute transversely to the trajectory of the movable contact and along said electrodes.

ANDRE CLERC, 

